You don't really need to block out other people's opinions. It is that you give those opinions power over your. It still comes back to your belief system. What beliefs do you have that say- what other people think matters to you creating the life you desire? If you were going to make a sandwich and everyone told you how crazy you were, you can't make a sandwich would that stop you??? I would guess not. You would know how silly those other people are. You could look into your beliefs about success, other peoples opinions, self-esteem, etc... Maybe you use what other people are saying as a scapegoat, so you don't have to follow through with something that would bring you joy or success.
Here is a page I put together on self-esteem, it has some powerful quotes that may help. Inspirational Self-Esteem Quotes